Functional-Style Array Prototypes

Let's face it. Chaining array functions is fun. But sometimes the built ins just aren't enough or don't make it precisely clear what you're trying to accomplish.

This library attempts to extend that functionality by adding functional-style, chainable prototypes to Array.

All methods treat the data as immutable and return new values.

Important Notes

• This will not overwrite any pre-existing prototype methods you may have already implemented.
• This should probably not be used in production, because, well, you're adding to the Array prototype. But I won't tell.
• If you have any suggestions on improving methods, feel free to create an issue.

Installation

Currently only available for Node 4+, or for use with the --harmony flag as they've been written in ES6 (mostly).

$ npm i --save fp_prototypes

Usage

Simple require the module and you're done. The prototypes are automatically added.

Example script.

require('fp_prototypes');

[1,2,3,4].reject(x => x === 3).tail().head();

Available Methods

adjust

Applies a callback to an array at a given index.

[1,2,3,4].adjust(1, x => x+1) // [1,2,4,4]

append

Similar behavior to concat but doesn't require a value to be an array. A non-array will simply be added as the last element.

[1,2,3].append(4) // [1,2,3,4]
[1,2].append([3,4,5]) // [1,2,3,4,5]

head

Returns the first element of the array.

[1,2,3,4].head() // 1

init

Returns all but the last element of the array.

[1,2,3,4].init() // [1,2,3]

last

Returns the last element of the array.

[1,2,3,4].last() // 4

prepend

Same behavior as append but prepends instead.

[2,3].prepend(1) // [1,2,3]
[3,4].prepend([1,2]) // [1,2,3,4]

reject

The opposite of filter. Truthy values will be removed. If no callback is supplied, the truthiness of each value will be used instead.

[1,2,3,4].reject(x => x === 3); // [1,2,4];

tail

Returns all except the first element of the array.

[1,2,3,4].tail() // [2,3,4]

take

Returns the first x number of items from an array

[1,2,3,4].take(2) // [1,2]

TODO

• drop (opposite of take)
• dropLast
• takeLast
• reverse
• merge
• diff
• unique